Create NSDate Monotouch

问题

I am trying to take a date string and turn it into a specific NSDate (eg. July 1, 1981), but I don't see and methods for setting the date. Does anyone know how to accomplish this? Perhaps convert a DateTime object to NSDate?

回答1:

The easiest way is to set it from DateTime.

REVISION: The NSDate conversion operators are now explicit, not implicit anymore! I updated the example below.

If you look at the NSDate prototype you will find two operators:

    public static explicit operator NSDate(DateTime dt);
    public static explicit operator DateTime(NSDate d);

These two will do the conversion for you.

Explicit conversion of NSDate to and from DateTime is quite good, but you must be aware that NSDate is always an UTC time and DateTime is default set to DateTimeKind.Unspecified (when read from database) or DateTimeKind.Locale (when set with DateTime.Today). The best way to convert without complicated time-zone computations is to force the right DateTimeKind:

    // Set NSDate:
    DateTime date = DateTime.Parse("1981-07-01")
    NSDate nsDate = (NSDate)DateTime.SpecifyKind(date, DateTimeKind.Utc);

    // Get DateTime from NSDate:
    date = DateTime.SpecifyKind((DateTime)nsDate, DateTimeKind.Unspecified);

回答2:

public static DateTime NSDateToDateTime(MonoTouch.Foundation.NSDate date)
{
    return (new DateTime(2001,1,1,0,0,0)).AddSeconds(date.SecondsSinceReferenceDate);
}

public static MonoTouch.Foundation.NSDate DateTimeToNSDate(DateTime date)
{
    return MonoTouch.Foundation.NSDate.FromTimeIntervalSinceReferenceDate((date-(new DateTime(2001,1,1,0,0,0))).TotalSeconds);
}

This should help

Alex

回答3:

Try this:

private static NSDate DateTimeToNSDate(DateTime date)
    {
        NSCalendar calendar = NSCalendar.CurrentCalendar;
        NSDateComponents comps = new NSDateComponents();
        comps.Day = date.Day;
        comps.Month = date.Month;
        comps.Year = date.Year;
        comps.Minute = date.Minute;
        comps.Hour = date.Hour;

        return calendar.DateFromComponents(comps);
    }

回答4:

public NSDate ConvertDateTimeToNSDate(DateTime date)
{
    DateTime newDate = TimeZone.CurrentTimeZone.ToLocalTime(
        new DateTime(2001, 1, 1, 0, 0, 0) );
    return NSDate.FromTimeIntervalSinceReferenceDate(
        (date - newDate).TotalSeconds);
}

public DateTime ConvertNsDateToDateTime(NSDate date)
{
    DateTime newDate = TimeZone.CurrentTimeZone.ToLocalTime( 
        new DateTime(2001, 1, 1, 0, 0, 0) );
    return newDate.AddSeconds(date.SecondsSinceReferenceDate);
}

Source : https://theweeklybyte.wordpress.com/2014/05/27/convert-datetime-to-nsdate-and-back/

回答5:

You want to look at the NSDateFormatter class :)

Your code will look something like this . . .

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"MMM dd, yyyy HH:mm"];

NSDate *parsed = [formatter dateFromString:dateString];

PS Example liberally copied from this question :)

来源：https://stackoverflow.com/questions/2148906/create-nsdate-monotouch

标签

.net

iphone

xamarin.ios

nsdate